首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
The World Space Congress 1992 took place after two Spacelab flights with important biological payloads on board, the SLS-1 (June 1991) and IML-1 (January 1992) missions respectively. Interesting experiments were carried out in 1991 also on the Shuttle middeck and on the sounding rocket MASER 4. The highlights of the investigations on these missions together with the results of relevant ground-based research were presented at the symposium.  相似文献   

2.
Tissue equivalent and Solid State Detector (SSD) measurements of the radiation environment inside the Mir space station were performed during the Antares mission in 1992 and long period after it. Interesting results about radiation measurements show (a) the South Atlantic Anomaly (SAA) crossing, (b) the increase of radiation near the poles and (c) the effects of solar eruptions (the most important one occurring in early November 1992). These data give also information about the dose and the quality factor of the radiation received by the cosmonauts during different missions.  相似文献   

3.
The Cosmic Radiation Environment & Activation Monitor (CREAM) was carried in high inclination (57.1 degrees) orbits on Shuttle missions STS-48 in September 1991 (altitude 570 km) and STS-53 (altitude 325 to 385 km) in December 1992. On both occasions the instrument observed an excess of counts due to protons of greater than 30 MeV in energy in the region off of South Africa where field lines of L=2.5 intersect low earth orbit. Meanwhile the Cosmic Radiation Environment and Dosimetry Experiment (CREDO) carried to 840 km, 98.7 degrees orbit on UOSAT-3 has continued to sample the high field portions of the L-shells around L = 2.5 from April 1990 until the present time. When careful subtraction of cosmic-ray contributions is made it can be seen that the March 91 enhancement persisted for approximately 8 months and explains the STS-48 observation. There would appear to have been a further increase produced by the 31 October 1992 flare event and seen by STS-53.  相似文献   

4.
We developed a chronically instrumented nonhuman primate model (baboon) to evaluate the central cardiovascular responses to transient microgravity induced by parabolic flight. Instrumentation provided simultaneous recording of high fidelity (Ao) and pulmonary artery (PA) pressures, right and left ventricular and atrial pressures, Ao and PA blood flow velocities and vessel dimensions, ECG and pleural pressures. Four daily flights in 1991 and five in 1992 were flown with forty parabola per flight. Animals flown in 1991 were not controlled for volume status. Animals flown in 1992 were studied in one of three conditions: 1) volume depleted by furosemide (DH), 2) volume expanded by saline infusion (VE), and 3) euvolemic (EU, no intervention, used for echo only). Mean right atrial pressures (RAP) during 1991 flights had a variable early microgravity response: increases in n=3 and decrease in n=3 (supine) and increases in n=5, decreases in n=2 (upright). In 1992 flights, DH, upright and supine, changed -10 +/- 4.1 mmHg, -3.2 +/- 2.2 mmHg, respectively (p < .05) compared to the pull-up phase. In contrast, VE changed (from pull-up to microgravity) +13 +/- 1.5 mmHg and +4.25 +/- 2.9 mmHg (upright and supine, respectively, p < .05). EU increased with microgravity +6.9 +/- .9 mmHg (upright only). LAP responses were similar, but more variable. Finally, heart chamber areas paralleled pressure changes. Thus, right and left heart filling pressure changes with sudden entry into microgravity conditions were dependent on initial circulatory volume status and somewhat modified by position (supine vs upright).  相似文献   

5.
ROSAT All Sky Survey observations of IRAS galaxies have revealed up to now a number of 10 optically non-Seyfert galaxies with X-ray (0.1–2.4) luminosities up to a few 1043erg · s−1 (Boller et al. 1992). The sources are brighter than previous detection limits of a few 1041erg · s−1 as found by Stocke et al. (1991) or Green, Anderson and Ward (1992) for Einstein sources. The optical classification is based on follow-up observations which indicate clearly the non-Seyfert (LINER and HII region-like galaxies) nature. Our investigations reveal that galaxies classified as non-Seyferts on the basis of optical spectroscopy may reach exceptionally high X-ray luminosities which are similar to that of Seyfert galaxies. On the basis of the present observational material we suppose a hidden low luminosity AGN in the centre of these objects as the source of energy production. The objects are of interest when evaluating starburst versus central activity.  相似文献   

6.
Proton fluxes obtained by two instruments carried on the ESA/NASA Ulysses spacecraft are reported for the period from launch in October 1990 till Jupiter encounter in February 1992. Proton energy ranges are 24-59, 71-99, 130-320, 320-2100 and > 2100 MeV. The Sun was very active during this period, the events of March 1991 being some of the largest of the solar cycle. The relationship between events on the Sun and the observed proton flux is discussed.  相似文献   

7.
The influence of microgravity on the repair of radiation induced genetic damage in a temperature-conditional repair mutant of the yeast Saccharomyces cerevisiae (rad 54-3) was investigated onboard the IML-1 mission (January 22nd-30th 1992, STS-42). Cells were irradiated before the flight, incubated under microgravity at the permissive (22 degrees C) and restrictive (36 degrees C) temperature and afterwards tested for survival. The results suggest that repair may be reduced under microgravity.  相似文献   

8.
日地共转扰动似稳结构及其反相现象在第21及22周再次显现,从而证实了上述发现是一种在长达世记的时间尺度内存在的普遍规律。包括1991-1992年内的百年地磁扰动资料还说明偶数太阳周的共转似稳结构扰动峰有逆太阳自转而线性性漂移的趋向。对即将来临的极小年前可能出现的共转扰动作了试验性的预测。  相似文献   

9.
Dynamics of the galactic cosmic ray intensity caused by their interactions with a shock front in the September 9, 1992 event has been determined. Corresponding variations of the cosmic ray intensity have been calculated for different stations of the world network of neutron monitors and muon telescopes of stations Nagoya and Sakashita. Comparison calculated results with observational data shows, in general, satisfactory consensus both on amplitude and in time. The developed method can be used for investigation dynamics of the solar wind disturbances precursors in the cosmic rays.  相似文献   

10.
We performed a search for ground level solar cosmic ray enhancements on the full five minute database of the Mexico City neutron monitor using wavelet filters and two different statistical tests. We present a detailed analysis of the time series of November 2, 1992, where we found a previously unreported increment matching the onset time of the impulsive phase of GLE 54, thus providing evidence of an effective detection of high energy solar cosmic rays.  相似文献   

11.
The power spectrum was calculated for the time series of the LDE-type flare occurrence during the last three solar cycles (the 20-th, the 21-st and the first part of the 22-nd cycle). LDE-type flares (Long Duration Events in SXR) are associated with the interplanetary protons (SEP and STIP as well), energized coronal arches and radio type IV emission. Generally, in all the cycles considered, LDE-type flares mainly originated during a 6-year interval of the respective cycle (2 years before and 4 years after the sunspot cycle maximum). The following significant periodicities were found: in the 20-th cycle: 1.4, 2.1, 2.9, 4.0, 10.7 and 54.2 of month; in the 21-st cycle: 1.2, 1.6, 2.8, 4.9, 7.8 and 44.5 of month; in the 22-nd cycle, till March 1992: 1.4, 1.8, 2.4, 7.2, 8.7, 11.8 and 29.1 of month; in all interval (1969-1992): 1. the longer periodicities: 232.1, 121.1 (the dominant at 10.1 of year), 80.7, 61.9 and 25.6 of month, 2. the shorter periodicities: 4.7, 5.0, 6.8, 7.9, 9.1, 15.8 and 20.4 of month. Solar variability has an extremely complex time dependence. The Sun is a multiperiodic system. The strong periodicities "near 155 and 270 days" were found also in the LDE-type flare occurrence.  相似文献   

12.
影响地球环境的太阳质子事件的时间过程   总被引:1,自引:0,他引:1       下载免费PDF全文
利用1966年以来的大量太阳耀斑以及相应质子事件的资料,分析研究了质子事件到达时间和极大时间同耀斑经度位置的统计关系.结果表明当耀斑位置处于经过地球的行星际大尺度场磁力线足点位置附近时,上述两种时间过程最短.这个结果支持了太阳耀斑粒子经日冕传播再向行星际空间传播的二阶段传播模型.   相似文献   

13.
本文根据1986年1月-1992年12月期间,130个1-8?的X级别的X射线事件与相应背景发射水平所作的分析,发现90%以上的X级X射线事件,都发生在X射线背景发射≥C1(10-6W/m2)水平上,这一统计规律,可从耀斑加速的非热电子对色球等离于体的加热得到合理的解释.   相似文献   

14.
The COMPTEL experiment on the Compton Gamma-Ray Observatory is designed to image celestial gamma radiation in the energy range from 0.75–30 MeV within a field of view of 1 steradian. It can locate stronger point sources with an accuracy better than 0.5° and is capable of mapping diffuse emission as well. The Galactic-center region was observed by COMPTEL for several 2-week periods in 1991/1992. These observations show evidence for 1.8 MeV line emission along the Galactic disk (attributed to radioactive 26Al), extending over at least 40 degrees in longitude.  相似文献   

15.
We present early results from the Far Ultraviolet Space Telescope (FAUST), which flew in March 1992 with the ATLAS space shuttle mission. The telescope provides wide-field images in the far ultraviolet (1400–1800 Å). Studies underway using the data obtained on this mission include establishing the brightness and distribution of far ultraviolet stars in the halo of our Galaxy, establishing the far ultraviolet properties of nearby galaxies and nearby clusters of galaxies, analyzing the diffuse galactic light, and searching for the origin of the extragalactic ultraviolet light. We discuss the instrument performance, and early results from these observations.  相似文献   

16.
We present Linear Energy Transfer (LET) spectra calculated for the 1990-1991 CRRES mission using the galactic cosmic ray (GCR) and solar energetic particle (SEP) models developed for the CRRES/SPACERAD program and presented by Chen, et al. 1992 at this conference. We discuss how the spectra vary with changes in the galactic cosmic ray and solar energetic particle models. Finally, we illustrate the application and significance of these results by using them to predict single event upset event rates in a sample integrated circuit memory device, a 256 x 4-bit bipolar static RAM (93L422).  相似文献   

17.
The ‘particles-in-a-box’ (PIB) model introduced by Talent [Talent, D.L. Analytic model for orbital debris environmental management. J. Spacecraft Rocket, 29 (4), 508–513, 1992.] removed the need for computer-intensive Monte Carlo simulation to predict the gross characteristics of an evolving debris environment. The PIB model was described using a differential equation that allows the stability of the low Earth orbit (LEO) environment to be tested by a straightforward analysis of the equation’s coefficients. As part of an ongoing research effort to investigate more efficient approaches to evolutionary modelling and to develop a suite of educational tools, a new PIB model has been developed. The model, entitled Fast Debris Evolution (FADE), employs a first-order differential equation to describe the rate at which new objects ?10 cm are added and removed from the environment. Whilst Talent [Talent, D.L. Analytic model for orbital debris environmental management. J. Spacecraft Rocket, 29 (4), 508–513, 1992.] based the collision theory for the PIB approach on collisions between gas particles and adopted specific values for the parameters of the model from a number of references, the form and coefficients of the FADE model equations can be inferred from the outputs of future projections produced by high-fidelity models, such as the DAMAGE model.  相似文献   

18.
In this paper we revisit the 1995 Kaman database of the SOCIT4 fragment characteristics with added analysis of a subset of the cataloged fragments from the test. This database was compiled from the last of a series of four hypervelocity impact tests conducted under a U.S. Department of Defense program in 1991–1992. This test targeted a flight-ready, U.S. Transit navigation satellite, yielding collision fragments in the size regime of sub-millimeter through tens of centimeters. Results in this database were used in the 1998 NASA Standard Breakup Model to represent characteristic length (size) and area-to-mass distributions of fragments smaller than 10 cm.  相似文献   

19.
北京天文台在2.84GHz频率上观测到的带短时标精细结构的微波爆发与日本YOHKOH卫星上HXT在1991年10月-1992年12月观测到的硬X射线爆发(HXB)事件作了比较,发现在20个微波精细结构爆发事件只有12个与YOHKOH卫星记录的HXB有对应关系.本文对1992年6月7日典型事件中2.84GHz与HXB共同存在的百秒量级的准周期振荡作了分析及源区参数的计算,并作了简要的讨论.  相似文献   

20.
We report the first detection of two soft gamma ray transients GX 354-0 and Nova Persei (GRO J0422+32) by the coded-mask telescope SIGMA. Only preliminary results are presented with regard to Nova Persei while special emphasis is given to the data on GX 354-0 which has been monitored during the 1992 February–April survey of the Galactic Center. GX 354-0 underwent two flares of about two week duration and its average spectrum is well described by a thermal Bremsstrahlung model or a broken power law whereas the Nova Persei spectrum seems to be similar to the one observed for GRS 1124-684 in Musca.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号